Conditioned suppression produced in rats by tones paired with escapable or inescapable shock.

Abstract

Gave 22 male wistar rats variable interval (vi) lever-press training for food reinforcement. 11 ss were then trained in a different environment to escape tone-signaled shock by jumping upward, exerting pressure against the chamber ceiling. 11 yoked controls were simultaneously exposed to tones and shocks, but shock termination was independent of responding. In cer tests conducted in the original vi chamber, tone presentations produced greater response suppression in inescapable-shock ss than in ss for which the tone had been paired with escapable shocks. It is concluded that stimuli associated with painful events over which the organism has no control become more fear inducing than stimuli associated with painful events which the organism can terminate. (PsycINFO Database Record (c) 2006 APA, all rights reserved)